Circuit interrupter



March 3, 1931. A. KUHNS CIRCUIT INTERRUPTER Filed Oc't 20, 1927 INVENTOR A flexamc/er Kal /m5 I I ATTORNEY Patented Mar. 3, 1931 UNITED STATES PATENT OFFICE ALEXANDER KfiHNS, OF BERLIN-OHARLOTTENBURG, GERMANY, ASSIGNOR TO WEST- INGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA CIRCUIT INTERRUPTER Application filed October 20, 1927, Serial No.

vide a circuit interrupter with an operating mechanism, the initial movement of which stores energy in a biasing member which is to be expended during the latter part of the movement of the operating mechanism.

The use of contact members movably I n'iounted on the bridging member of oil circuit interrupters, and the use of springs between the contact member and the bridging member, which are placed in tension during the opening movement of the breaker, is well known in the circuit-interrupter art.

The use of such springs for each pair of contact members has the drawback that the bridging member may not remain aline d properly, so that only one of the springs is placed under tension, and so pulls out its contact member while the other contact member remains in its closed position. This may resalt in an are continuing between one pair of contact members to damage their abutting surfaces, which must be repaired before the circuit interrupter can be again em 'iloyed.

In order to overcome this drawback, my oil circuit interrul'iter is so designed that the contact members are rigidly mounted on the bridging member, and the bridging member, or the switch rod crank member, or both are connected to the actuating means through a spring.

My invention will best be'understood by referring to the drawings, in which,

Figure 1 is a view, in elevation, of a particular embodiment of my invention,

Fig. 2 is a similar View of another embodiment that my invention may assume,

Fig. 3 is a similar view combining the embodiment of my invention shown in Figs. 1 and 2.

My invention comprises, in general, a circnit interru 'iter 1 having a bridging member 227,487, and in Germany October 20, 1926.

2, a lift rod 3, a crank arm 4; and a biasing member 5 cooperating to operate the bridging member 2 to quickly open the circuit interrupter 1 in a manner to be more fully described hereinafter.

Referring to Fig. 1, the contact members 6, supported from the bushings 7, are connected with each other by means of a bridging member Member 2 is movably mounted on the lift rod 3, being supported thereon by an expanded head 8 at the lower end of the rod. A pressure spring 5 is located on the lift rod 3 between a lug 9 thereon and the bridging member 2. The lift rod 3 is moved downwardly by means of a crank arm 4 mounted on a shaft 11. Upon turning the shaft 11, the lift rod 3 is moved downwardly to compress the spring 5. The engagement between contacts 6 and bar 2 is so tight that considcrable force is required to cause their separat-ion. Preferably, this is so great as to hold them together, until the projections at the ends of the member 9 strike against the bridging member 2 to cause it to move out of engagement with the fixed contact members 6. The spring 5 stores energy during this operation andgives it to the bridging member 2 to effect a sudden separation of the contact members.

In the design shown in Fig. 2, the driving crank 12 is loosely mounted on a. shaft 11 and there is provided a second crank arm 13 which is rigidly connected to the driving shaft 11 and is loosely or yieldingly connected to the loose crank arm 12 by means of a spring soon as the bridging member 2 has been dis- 8?- engaged from the fixed contact members 6, the stored up energy in the spring 14 will effect a quick separation of the contact members.

In the design shown in Fig. 3, the driving vploy ed heretofore.

crank 12, the crank arm 13 and the spring lt of the Fig. 2 are combined Withthe lift rod 8, the spring member and the lug 9 of the Fig. 1 to form a structure having still greater mechanical flexibility.

Assuming thecircuitinterrupter of Fig. 1 to be in its closed position as shown in the drawing, the counter-clockwise movement of the crank arm 4: compresses thes spring member 5 to store'energy until the lug '9 strikes the bridging member lhe bridging member 2 is thus moved downwardly andis accelerated by the energy that was stored in the spring member 5, duringrthe'initialmovement of the arm 4.

It'will thus be seen that I. am 'able to obtain a high-speed separation of the Contact members 6 without using any greater arc of travel of the crank armt than has been em- This is:accomplished by utilizingtheiirst portion of the movement of t'hearm' in storing energy in abiasing memher to be applied, as air-accelerating force, duringthe last portion of the movement of the bridging member 2. My invention may,

therefore, he employed.onpresent apparatus,

when an increase in the speed of opening is required, by the mere addition; of the. biasing structure shown in'thefi'gures and described above.

:Fhe mode of operation of the modifications shown in Figs. 2 and 3is so nearly like that of Fig, 1; thatseparate description thereof is hardly necessary I do not wish to be restrictedto the specific arrangementof parts hereinset: forth, as various modifications thereof maybe effected without departing from the spirit and'scope of my invention. I desire,therefore, that only s uch limitationsshall be imposed as are indicatedin the appended claims] I claim as my invention: Y

1. In an operating mechanism, a plurality of biasing means stressed in sequence during the initial movement-oft'he said operating mechanism, to store energy that is'expended during the final movemontcft-he said mechanism.

In an operating mechanism for a circuit interrupter, a plurality of .bi'asing means adapted to store energyon' the initial movement of'the said operating mechanism, means for producing the initial movement of said operating mechanism, means't'hereaft-er torelease the circuit interrupter by imparting movement directly fromthe operating mecln anism'to the movable element thereof and means to cause said movable element to be acceleratedby expenditure of'the energy of said energy-storingmeans.V

V 3. In combination with an operating mechanism for a, circuit interrupter that comprises contact members supported by a bridging member, a liftrod for the bridging member loosely connected thereto and to the operating mentioned arm, a bridging member loosely mounted on the lift rod, means on the lift rod for limiting the movement of the bric ging memher'thereon and biasing means between the bridging member and one of the said limiting means.

lntestimony whereofll have hereunto sub- "scribedmy name this tith. day of'Septemher,

ALEXANDER KUHN s. 

